Cirrifera genitoductus sp.n. (Platyhelminthes, Proseriata, Coelogynoporidae) from the Belgian coast, with observations on its ultrastructure and its significance for the taxonomy of the Coelogynoporidae

Cirrifera genitoductus sp.n. (Platyhelminthes, Proseriata, Coelogynoporidae) is described from sandy beaches at the Belgian and Northern French coasts. The species is characterised by a cirrus with small spines, all of the same size, a prostate vesicle far behind the copulatory bulb, a long genito-intestinal duct and a pair of large gland complexes behind the genital pore. An identification key for the Cirrifera-species is given as are some data on the ultrastructure. A brief discussion on the character distribution within the Coelogynoporidae shows that the discovery of a species of Cirrifera with a genito-intestinal duct makes the demarcation of the genera even more blurred than it already is.